[Terrapreta] Commercial charcoal VM content

[Michael J. Antal, Jr.]

Hi Tom: thanks for your very informative posting.

Readers of Energy & Fuels may recall an article from my lab "High-Yield
Biomass Charcoal" (Vol. 10, No. 3, 1996, pp. 652-658) that lists the
following proximate analyses of commercial barbeque charcoals:

Kingsford briquette 	36.4% VM	17.2%  ash
Kiawe lump charcoal	28.3% VM	01.96% ash
Mesquite lump charcoal	 9.0% VM	04.17% ash

The very high VM content of the Kingsford briquette charcoal makes it easy
to ignite.  The mesquite charcoal is tough to ignite.

Best wishes, Michael.

-----Original Message-----
From: Tom Miles [mailto:tmiles at trmiles.com]
Sent: Wednesday, March 07, 2007 8:10 AM
To: 'Michael J. Antal, Jr.'; terrapreta at bioenergylists.org
Subject: RE: [Terrapreta] Charcoal properties II



All,

Michael wrote:

"Since well-characterized charcoal samples are not easily available, I
suggest that you document everything you know (e.g. its source, the
feedstock, its history, etc.) about the sample you are testing, and that you
set aside a small sub-sample of the charcoal (ca. 100 g or more) for later
testing in the event that you find the charcoal to be particularly
beneficial (or detrimental) to plant growth.  Without well-characterized
charcoal samples, progress can still be made if the charcoals that prove to
be particularly beneficial (or detrimental) can be identified and tested
after the fact."

If the volatile matter content is the distinguishing characteristic of the
charocal then we can use that as a reference. The Ash and Moisture Content
would also be a product of the proximate analysis.

I uploaded a post to the Terra Preta site called "Factors Influencing
Charcoal Quality" that I posted to the biomass cooking stoves site last
year.
http://terrapreta.bioenergylists.org/charcoalquality
If a target quality is 20%-25% volatile matter then the heat treat
temperature for the wood samples cited would be about 400-450 C for about an
hour. I understand that commercial charcoals contain about 14% volatile
matter.

Charcoals used in the Indonesia work by the Forestry Research and
Development Agency and the Japan International Cooperation Agency using a
flat kiln were tested at 20-25% volatile matter (VM) and 4%-6% ash. See:
"A Flat kiln and Utlization of Sawdust Charcoal"
http://terrapreta.bioenergylists.org/?q=node/124
And
"Trials on Some of Charcoal Production Methods for Carbon Sequestration in
Indonesia Kazuya Ando, Nobuo Ishibashi, Gustan Pari, Kiyoshi Miyakuni 2004"
http://www.georgiaitp.org/carbon/PDF%20Files/Posters/AndoPoster.pdf

Other chemical properties that I see tested are: pH, Cation Exchange
Capacity (me/100g), Exchangeable cations (me/100g) K, Ca, Mg, Na, and
probably available phosphate.

I'm sure that organizations like Cornell have databases of these qualities
and a good notion of how charcoal quality impacts plant response in soils.

What values do we have for lump charcoal purchased in stores for barbecue,
"horticultural charcoal" or other common sources. I'm sure that producers
like Kingsofrd/Chlorox could produce the quality of charcoal required by the
truckload.

Tom Miles